Bag of Golding

This small pouch appears to be nothing more than a
beautifully decorated bag, but within is an extradimensional
space that can hold 5 square feet of currency. There are four
large beads threaded through the string on the front of the
bag that are colored copper, silver, gold and platinum. Sliding
these beads to the right causes all currency placed into the
bag or withdrawn from the bag to be of the designated
currency type. The pouch can open to a maximum of 12
inches and any non-living, non-magical item that passes
through the threshold of the bag is instantly converted to its
value of the selected currency.
If this bag is placed within another extra-dimensional
space, the pouch is destroyed and all of its contents explode
violently up to 300 feet in all directions in the form of coins of
all varieties.